Protect Your Plants from Frost

After weeks of unpredictable weather, things are finally starting to cool down as we settle into December. With snow and frost already in the books this winter, it’s time to start taking stock of your garden to be sure they can survive the chill.

You may be wondering how cold is too cold for your plants? The temperature at which plants freeze can vary, so there’s no hard and fast rule. Plants have designated hardiness levels, which helps identify the lowest temperature the plant can withstand before suffering from negative results.

Tropical plants and frost-tender plants cannot survive freezing temperatures, which is why they flourish in warmer climates. Fully hardy perennials, shrubs and trees, however, go dormant in the colder months, allowing them to survive the freezing temperatures and bloom again come spring. Not sure where your plants fall? Make sure you do your research before prepping your garden for a frost.

Once you know your plant’s hardiness level, consult this table to know when you need to take extra steps:

Temperature

Type (Frost or Freeze?)

Effects on Plants

28 degrees Fahrenheit for a few hours

Light frost, light freeze

Usually harms tender plants. Ice forms on the outside of the plant.

25-28 degrees Fahrenheit for several hours

Hard frost, killing frost, moderate freeze

Damages foliage and blossoms. Ice forms within the plant, causing plant cells to burst. Will kill back root-hardy perennials and damage crops.

Below 25 degrees Fahrenheit for several hours

Severe freeze

Causes damage to many plants, usually through desiccation (drying).

So, you know the hardiness of your plants and you know what type of frost or freeze you’re expecting – how do you protect your plants? There are several things you can do to keep your plants safe from the cold:

Cover the plant with a sheet or blanket before nightfall to keep it insulated – for added insulation, you can add plastic over the blanket. Do not use just plastic without a blanket or sheet to cover your plants, as plastic can damage the plant. If you use this method, don’t forget to remove the cover in the morning to avoid condensation and additional freezing.

Water your plants thoroughly before a freeze. This may seem counterintuitive, but it can prevent desiccation and add insulating water to the soil and cells of the plant.

Keeping your garden safe from frost damages is quick and easy. The best way to maintain a thriving garden is to plan ahead and practice prevention – plant weather hardy plants meant for your climate in your garden. If you’d like to plant tender plants, use containers that can be easily brought inside during the colder months.